ArduCopter-3.1 released!

After months of testing AC3.1 is finally available in the Mission Planner and GitHub.

Warning #1: If the vehicle is left landed (but armed) while in AltHold or Loiter mode for more than a few seconds, the vehicle may suddenly jump into the air the moment the pilot raises the throttle above zero.  The reason is the baro altitude may fall while the vehicle is sitting on the ground.  In AC3.2 this bug is fixed because we reset the target before take-off.

Warning #2: Motors will spin (slowly) by default as soon as the copter is armed!  You can switch this feature off by setting the MOT_SPIN_ARMED parameter to zero.

Warning #3: if you see "Bad Gyro" on the HUD then you may have a blown 3.3V regulator.  See this thread for details.

Warning #4: if you use a sonar set the SONAR_GAIN parameter to 0.8 or lower

Warning #5: Trad Heli users should now connect their main rotor ESC to APM's RC8 output

Warning #6: Trad Heli BUG causes loss of collective control in ACRO mode if swash type set to flybarred (i.e. not flybarless).  Will be fixed in AC3.2.


The major improvements over AC3.0.1 are (full list here):

1. Pixhawk support (Tridge & PX4 development team)

2. Autotune of Roll and Pitch gains (Leonard/Randy)

3. Drift mode (Jason)

4. Improved Acro (Rob/Leonard) and new Sport mode (Leonard)

5. Arming, Take-off, Land in Loiter or AltHold

6. TradHeli improvements (Rob) including:

a) support for direct drive tail rotors

b) smoother ramp-up of main rotor

c) reduced collective for better control in stabilize mode (STAB_COL_MIN, STAB_COL_MAX params)

7. Support for SingleCopter (Bill King)

8. Performance improvements resolve AltHold troubles for Hexa & Octacopters

9. Safety Improvements:

a) GPS Glitch detection (Randy)

b) Motors spin when armed (Jonathan Challinger)

c) crash detector shuts off motors if copter flipped for 2secs

d) batt failsafe option to RTL instead of LAND, gps failsafe option to trigger AltHold instead of Land

e) more pre-arm checks of inertial nav speed,

10. Bug fixes:

a) optical flow working again (although performance is still not great because not integrated with inertial navigation)

b) ROI working (use DO_SET_ROI command)


How to upgrade:
Click on the MissionPlanner's Initial Setup >> Install Firmware screen.  The version numbers should appear as "ArduCopter-3.1", then click the appropriate frame icon and it should upgrade as per usual.

Special thanks to Marco and the many beta testers on the AC3.0.1 thread who put their copters at risk during the testing of this new version and uncovered many problems so that you don't have to!  Here are some of their videos: loiter in wind, patio sonar, autotune, autotune2, roi, beach, acro, vrbrain, tricopter, train spotting, radio failsafe, the tree, double loiter


If you haven't seen it recently, please check out the ArduCopter wiki.


Feel free to post comments below and we're going to use the new APM Forum for support issues so please post your support requests there.

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                  • Says to me that the motors are more efficient spinning in one direction than the other.  Mine also have always showed the same imbalance and I have flown the quad almost daily for a year now with no problems. 

                    I also use RcTimer 30A esc. My motors are RcTimer hp2212-1000kv

    • I see Compassmot is not made, please make and the copter flies properly

      • When I made compassmot, I've this error :

        Failed! Compensation disabled. Did you forget to raise the throttle high enough?

        I've remade more 15 tests and I've same error. I've see the 

        no more success ....

        • Please go to Mission Planner click initial setup and click Optional Hardware.  Go to Battery Monitor and specify "Voltage and Current". Also specify the type of APM Ver to "APM 2.5 + 3DR power module".  Now go to Terminal and do the Compassmot... It should work.  I am just trying to help.

  • I tried to post my problem on APM forum last wednesday, but no response or dialog. I know you're busy, but maybe there will be time to look at logs.
    "Today I tried the loiter mode on a new quad and had a sudden disaster. The althold was working very well and I had flown for about 3 minutes before switching to loiter and when I switched to loiter it was stable for a short time and then it suddenly got 2 or 3 power surges and significant altitude gains. At that time I switched back to althold mode and lowered the throttle and the motors quit and it dropped like a rock and broke an arm. Looking at the log shows the throttle surges but I can't see why that would have happened because the altitude was pretty stable until the surges.I did notice that the accelz vibration increase corresponded with the throttle out increases. I don't know if the vibration increases caused the throttle increase or if the throttle increase caused the vibration increases.

    Maybe someone can see something in the logs I am missing and I appreciate the help."
    Thanks for any insight you can give me.

    2014-03-04 14-57-05.log

  • Hi...I,m having a brain fart, old
    Been searching mission planner.. When I activate RTL, it flys backward,sideways.. Where is the command to make it turn heading towards home in mission planner..
  • Moderator

    Built a nice tricopter which flies really well after flying my quad for a long time. During the second flight having tested everything on the first, I switched to Alt_hold and the Tricopter just dropped like a stone fortunately onto grass so no damage. The Ning search is so bad on this site that it's almost useless so does anyone know why or what I need to check?

  • Hi Randy, kindly give us a clue on when this AC3.2 will be release? 


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